Retinoids are biologically active chemical compounds related to Vitamin A. Retinoids are used, among other areas, in the fields of dermatology and cosmetology. A variety of non-retinoid compounds are known that exert anti-inflammatory action, anti-microbial action, and other actions, such as immunomodulation and an ability to increase skin peeling, when applied topically. Such non-retinoid active agents include antibiotics and other anti-bacterial compounds, steroids, non-steroid anti-inflammatory drugs (NSAIDs), as well as other anti-inflammatory agents that are not conventionally categorized as steroids or NSAIDs. The antibiotics used in the topical compositions include tetracycline, erythromycin, and clindamycin. Benzoyl peroxide, which exerts its antibacterial action via its potent oxidizing properties and stimulates skin peeling, is another common non-retinoid active agent included in topical formulations. Dapsone, a compound known to have anti-inflammatory, anti-bacterial and immunomodulatory effects, is one more example of a non-retinoid active agent used in topical formulations.
Acne is a group of common skin conditions characterized by the so-called “acneiform” or acne-like skin eruptions, which can be contaminated with bacteria, such as Propionibacterium acnes, and can also be marked by inflammation. Acne tends to occur in the areas of skin where the sebaceous glands are most active, such as the face. Acne is associated with psychological trauma, and, if left untreated, can lead to scar formation and disfigurement.
Classification and the diagnosis of various acne conditions can be complex, and even contradictory. Given this complexity and unpredictability, medication and other therapies, are often developed on a trial-and-error basis in order to determine the most effective course of treatment for a particular patient. The outcome of any particular acne treatment regimen greatly varies from patient to patient, as well as throughout treatment of a particular patient. In addition to the complexity and variability of acne conditions, treatment efficacy can be greatly affected by a patient's compliance with the treatment regimen. Patient compliance during acne treatment may be influenced by side effects, which, for topical mediations, commonly include redness, itching, and skin peeling. The complexity of the drug regiment can also negatively affect patient compliance, particularly where two or more different topical medications are prescribed simultaneously. Another factor that negatively affects patient compliance is the cost of a drug regiment, which is considerably higher when multiple medications are prescribed. In some countries, acne is considered a cosmetic problem, and acne treatments are not covered by insurance plans, thus further increasing patient's treatment costs. Certain compositions for treatment of acne are available. Many of the available compositions include one active agent known to have anti-acne activity. Stability of compositions with multiple anti-acne agents can be problematic. Also, these compositions can be difficult to manufacture.
The problems described above are not confined to the treatment or acne, but are also applicable to a variety of other skin conditions, including, but not limited, to conditions or classes of conditions with complex or unknown etiology and that are difficult to classify or diagnose, in which, nevertheless, topical application of agents are known to be effective at least in some cases. Examples of such conditions or classes of conditions include psoriasis, rosacea and ichthyosis.
Accordingly, there is a continuing need for compositions and methods used in a treatment of a variety of skin conditions, such as acne, in which topical application is potentially effective. In particular, topical compositions comprising retinoids and methods are needed that would, for example, exhibit improved effectiveness, reduced side effects, or both, when used in a particular patient with a skin condition. Such improved topical compositions comprising retinoids and methods of their uses are also needed to improve treatment of patients with acne or suspected acne. The compositions and methods provided herein address these and other needs in the art.